Dallas (CNN) -- Sweltering heat continued to grip much of the South on Friday as temperatures soared to 109 degrees in Dallas and 110 in Oklahoma City.

In all, the National Weather Service this week issued heat advisories for parts of 15 states stretching from a sliver of Southern California to North Carolina. There are few signs of relief for residents throughout Texas as the state continues to struggle with one of the most severe droughts on record.

Business and water levels are evaporating in the heat at Lake Houston, where officials estimate a quarter of an inch of water dries up each day, CNN affiliate KHOU-TV said.

"Summertime, normally we have cars lined up on the weekends trying to get in here. This year, nothing," said Wayne Machann of Lake Houston Marina.

In Pennsylvania, passengers on an Amtrak train were stranded in the heat for hours Thursday evening after the train abruptly lost power, one of them said.

Haylee Harris, 27, who was on her way to Lancaster to celebrate her fiance Ryan Picchini's birthday, told CNN there was a loud "bang" before the train inexplicably coasted to a halt.

Harris, who was sitting in the car with the conductor, said her car was full because the train left Penn Station in Philadelphia at the tail end of rush hour. Though the conductor told passengers not to move between cars to conserve cool air, Harris said families with younger children struggled and eventually relocated to escape the heat.

Amtrak "had nothing, they didn't have water, no food -- and we didn't have dinner so we were sharing rice cakes between two of us and one bottle of water," she said.

It took two hours for another train to pull alongside and rescue the stranded passengers. Harris said conductors never offered an apology or explanation for the problem.

Amtrak officials didn't immediately respond to requests for comment.

Temperatures reached a high of 86 degrees in Pennsylvania Thursday.

The heat took a deadly toll on athletes across the nation this week. DonTeria Searcy, a 16-year-old high school student, died Tuesday after he passed out after a morning practice at a Florida football camp, the local sheriff's department said.

Another 16-year-old student, Forrest Jones, died Tuesday in a hospital after he passed out during a football practice at an Atlanta-area high school, school administrators said.